Am.  Jour.  Pharm  ) 
Dec,  1877.  j 
Street  Dust. 
593 
cities,  contained  35  per  cent,  of  metallic  iron,  given  by  the  shoes  of 
the  horses  to  the  stones,  besides  from  30  to  40  per  cent,  of  good  glue 
from  the  hoofs.  These  data  were  by  no  means  represented  as  excep- 
tional ones,  it  being  stated  that  they  did  not  vary  much  for  a  period  of 
over  two  months.  The  glue  as  well  as  the  iron  were  intended  to  be 
recovered,  the  former  very  probably  by  extraction  of  the  dust  with 
boiling  water,  the  latter  by  reduction  of  the  resulting  insoluble  residue, 
now  containing  over  50  per  cent,  of  metallic  iron,  in  small  blast-furnaces. 
Thinking  that  the  dust  of  the  most  active  thoroughfares  of  our  smoky 
city  should  fully  equal  any  "  European  "  dust,  at  least  in  regard  to  the 
percentage  of  iron,  I  collected  samples  from  different  parts  of  our 
city,  and  subjected  them  to  analysis,  with  the  following  results: 
Dust  from  Thirtieth  and  Smallman  streets,  Pittsburgh.  Sample  taken  Sept.  22, 
1877- 
Moisture,  . 
Carbonic  acid, 
Glutin,  ....  0-9210 
Bitumen  and  other  volatile  organic  matter,  17-5720 
Fixed  carbon,  .  .  .  26-1027 
Silicic  acid,  .  .  .  30*4314 
Phosphoric  acid,  .  .  .  21982 
Sulphuric  acid,       .  .  .  0-9633 
Ferric  oxide,  .  .  .  12*2203 
Alumina,  .  .  .  2*3132 
Manganic  oxide,  .  .  .  0*0625 
Lime,  ....  32174 
Magnesia,       .  .  .  .  1-4720 
Alkali  chlorides,     .  .  .  0-2330 
Ammonia,  ....  trace 
Loss,       ....  0-0480 
1-2050  per  cent.  ] 
1  '0400 
Total  loss  on 
ignition, 
46  8407  per  centf 
Ash, 
53*1593  per  cent. 
IOO'OOOO 
Metallic  iron  =  8-55  per  cent. — in  HC1  extract  6-74  per  cent.  Glutin  =  0-921 
per  cent,  in  aqueous  extract.  Soluble  in  water  rio  per  cent,  (leaving  0*2  per  cent, 
ash).  Ashes  on  ignition,  subsequent  to  extraction  with  hydrochloric  acid,  41*5  per 
cent. —  soluble  Si02=  0*31  per  cent. 
Ashes  from  samples  of  dust  taken  from  different  parts  of  said  streets  amounted  to 
50-25,  50-91,  5r92)  49'94>"  5376,  52  25  per  cent. 
Samples  of  dust  taken  from  center  of  crossing  of  said  streets  : 
Moisture,  .  .  .  .  1*20  per  cent. 
Volatile  organic  matter,  ,  .  .  18*65 
Fixed  Carbon,  ....  27*90 
Ash,  .....  52*25 
3* 
